1. The Field of the Invention
This application relates to a system used to measure the functioning of a user's feet when involved in activity and more particularly includes a device for positioning between the support surface of footwear and the foot of a user supported on the footwear to sense the functioning of the foot as the user moves that foot. More particularly, this application relates to a sensor pad that is positioned on or above the support surface of an item of footwear that detects the force exerted by at least one portion of the user's foot with the user positioned on and supported in an upright position on the footwear and also to sense the velocity and acceleration of the user's foot.
2. State of the Art
When standing upright, a human is typically supported by or deemed to be standing on his or her two feet. It is generally accepted that each foot has three areas of support, namely the heel, the ball (behind the big toe) and the outside (behind the little toe). It is also known that many people have legs of different length and feet of different size. In turn, the weight of an upright person may not be evenly distributed between left and right legs and/or, in turn, between left and right feet. In addition, the feet of a user may be oriented so that the three areas of support are not in a plane. In turn, the weight of the user is borne unevenly between the three points of support.
A human or other biped can engage in a wide variety of activity that involves operation of the one or both of the user's feet. That is, a user can engage in walking, jogging and running. In sports, the user is typically involved in one of these activities in one form or in combinations. For example, sports that involve movement of the feet directly and indirectly include, but are in no way limited to, track and field, skiing, skating, bowling, soccer, football, basketball, hockey, lacrosse, golf, baseball, tennis, squash and fencing. In effect, all such activity involves movement of the body and/or feet in a way that the weight or force on the feet and, in turn, on the points of support will vary. For example, in tennis, the user may run quickly and stop abruptly to reach a ball.
For many reasons it is desirable to know the relative distribution of forces between each of the points of support of a foot, the distribution of weight between feet, and the weight on each foot. Devices to effectively measure the weight on each of the points of support and the distribution of weight between feet as well as to measure the forces or weight one each foot are unknown. At the same time, it may be desired to know the velocity of the foot and the acceleration of the foot as it is being moved by the user in one direction or another to evaluate the movement.